What was found
(CAN) DURING ENGINE START, FLIGHT CREW DETECTED ELECTRICAL BURNING ODOUR AFTER SELECTING BOTH ENGINE CONDITION LEVER FROM FEATHER TO MIN. LEFT AC VM PHASE A, B, C AND RIGHT AC VM PHASE A, B, C ALL CIRCUIT BREAKERS POPPED. FLIGHT CREW THEN SHUT DOWN BOTH ENGINES AND DEPLANED PASSENGERS.MAINTENANCE FOUND AC POWER MONITOR PANEL WAS SOURCE OF ODOR. PANEL CONNECTOR PINS X, Y AND Z WERE PUSHED BACK. PANEL INTERNAL PC BOARDS SHOWED EVIDENCE OF BURNING. AIRCRAFT SIDE CANON PLUG PINS Y AND Z WERE BURNT. CANON PLUG 2420-P1 REPLACED, AC POWER MONITOR PANEL REPLACED, AND 12 INCHES OF WIRES 20016B-22 AND 10016C-20 REPLACED DUE TO HEAT DAMAGE.